1. Field of the Invention
This invention relates to a rectifier regulator system adapted to receive power from a source of AC power such as a permanent magnet or rotating field alternator and supplying direct current to a load such as a battery and vehicle electrical system. This regulator contains components for supplying the usual functions for rectifying the AC power and controlling the output voltage to the battery or the load. In addition components are included to prevent the application of dangerous and destructively high voltages to the output lead in the case where the battery or other load is intermittently or permanently opened with the system operating. In addition circuitry is included to turn off an auxiliary output in the event that the load voltage drops below a selected level thus preventing failures of load items which may be damaged by operation with abnormally low voltage applied.
2. Description of Prior Art
Many systems for rectifying the output of an alternator and controlling the charging of the battery are known in the art. An example would be applicant's U.S. Pat. No. 4,791,349. Some prior art circuits have included protection to prevent high voltages from appearing at the battery terminals if the battery is open circuited. Typically in the prior art this has included electronic means to short circuit the source of AC power for the entire time that the battery is, open thus requiring high current components and large heat sinks. In some other prior art circuitry if the battery is completely open and the voltage goes to zero, no power is available to turn on the components that normally allow and control the flow of power to the load. Thus after the first alternator cycle no power is dissipated in the shunt device. This type of circuitry in the prior art while eliminating the need for the large heat sink, however, will fail very quickly if the battery is at an intermediate state between normal characteristics and open circuit.
Also known in the art are systems such as described in applicant's U.S. Pat. No. 4,664,080 for limiting the speed of an internal combustion engine by removing the ignition in response to certain operating or signal conditions. Such systems may receive a portion of their power or a signal from the vehicle battery system such as is charged by the electric power system of the present invention. Under certain conditions of abnormally low battery voltage such as could be created by internal short circuits in the battery, speed limiting apparatus of the type or functional equivalent of that described in the above mentioned U.S. Pat. No. 4,664,080 may produce erratic turning on and off of the ignition, thus creating back firing in the engine which in some engine types could cause severe engine damage. An auxiliary output on the circuit of this present invention is intended to be connected to the input of such speed limiting apparatus, completely turning off such apparatus under abnormally low battery voltage conditions.
The objects and purposes of this invention are as follows:
(1) To produce a simple, light, inexpensive and highly efficient system to rectify and regulate the output of an alternator and produce direct current suitable for recharging a battery or operating the electrical system of a vehicle, and to include in that system means for sensing an intermittent or complete open circuit or partial open circuit of the battery and in response to that condition to turn off the output of the regulator and prevent the creation of abnormal voltages at the battery terminals.
(2) To perform the functions in 1 above without the necessity of large heat sinks or continually conducting the maximum output of the AC source through components within the regulator when the battery circuit is open or intermittently open.
(3) To provide an auxiliary output of the regulator with the voltage at the auxiliary output being abruptly reduced to zero when the voltage of the battery goes, even momentarily, below a predetermined, abnormally low limit.